الفهرس 
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Abstract
Obesity is one of the most rapidly increasing worldwide health care challenges, confronting the medical and scientific community. And obesity rates are increasing annually, making obesity and its related conditions a major public health problem. (William R et al., 2011).
Therapeutic lifestyle actions like dieting and exercise and weight loss drugs deliver modest long-term weight loss in obese individuals. Highly intensive dieting and an exercise program are capable of yielding significant weight loss; however, this is almost ubiquitously transient (Heath V et al., 2011)
Bariatric Surgery procedures are currently the most effective method for long-term weight reduction in patients with body mass index greater than 40 or greater than 35 with coexisting co morbidities such as T2DM, cardiopulmonary problems, or joint disease (Brolin RE 2002).
Roux-en-Y Gastric Bypass (RYGB) combines both restrictive and malabsorptive procedures. This surgery is the most commonly performed restrictive and malabsorptive procedure done today (Dimitrios J et al., 2010).
Ghrelin, a peptide hormone predominantly produced by the stomach. Ghrelin is today predominantly viewed as a central modulator of energy homeostasis (Castaneda et al., 2010).
Ghrelin induces weight gain by stimulating food intake in mammals (Hayahida T et al., 2002) and (Flier JS et al., 2002).Ghrelin is involved in the dysregulation of hunger sensation and long-term body weight in human obesity (Cummings DE et al., 2002).
The present study was carried out to evaluate the short term effects of Roux-en-Y gastric bypass (RYGBP) in comparison with diet induced weight loss effect on ghrelin secretion and its relevance on food intake and body weight changes.
Subjects were divided into three groups, Group (1): 20 extremely obese adults who had undergone a proximal Roux-en-Y gastric bypass, aged (31.2±6.4) years with BMI of (48.9±8.9). Group (2): 15obese adults who had undergone diet induced weight loss, aged (32.0± 7.4) years with BMI (36.3± 5.5). Group (3) 10 apparent healthy normal weight subjects matched for age and sex, aged (30.3± 5.7) years with BMI (23.6 ±1.4) served as the control group.
The subjects under the study were subjected to the following:
(4) Full medical history taking.
(5) Through physical examination with stress on anthropometric measures e.g. (Weight, Height and BMI)
(6) clinical assessment including
a) Blood pressure
b) Laboratory investigations including the following:
• Determination of Fasting serum glucose level.
• Determination of lipid profile including total cholesterol (TC), triglycerides (TG), (HDL-C) and (LDL-C).
• Determination of Fasting serum ghrelin level.
The results of the present study revealed:
Obesity (Group 1&2) is associated with mildly decreased levels of circulating ghrelin, when compared with the control lean group (p<0.001*).
The beneficial effects of RYGBP on body mass, and weight loss as In the present study a significant weight loss was reached at 6 months post-operative, the obese patients had lost approximately (26.9.±7.3%) of their initial BMI after RYGBP. while percent BMI reduction with that of approximately (13.5.±5.5%) induced by a diet protocol of similar duration in patients of similar age but less BMI at study entry.
The fasted ghrelin concentration is significantly lower post-RYGBP compared to pre-RYGBP. The mean ghrelin profile decreased after weight loss as compared with before weight loss.
Plasma ghrelin increases following diet-induced weight loss as compared with before weight loss.
The results of lipid profile components showed significant higher level of serum cholesterol, serum TG and LDL-C in obese adults (Group 1&2) when compared with the control group. HDL-C level was lower in the obese than in the non–obese adults (p<0.001*).
After Roux-en-Y gastric bypass (RYGBP) total cholesterol, LDL cholesterol, triglycerides, were significantly reduced (P < 0.001 for all). Inversely, HDL cholesterol disclosed a significant rise (P < 0.001).
Weight loss during the dietary program led to improve in Serum lipid profile as total cholesterol, LDL cholesterol, triglycerides, were reduced (P < 0.001 for all). Inversely, HDL cholesterol disclosed a mild rise (P < 0.001).
Significant negative correlation between fasting serum ghrelin (ng/dl) and (Weight (kg) and BMI (kg/m2) before and after intervention) in gastric bypass group and diet group (p<0.001**).
Serum ghrelin had a significant negative correlation with LDL-c TC and TG and a significant positive correlation with HDL-c before intervention in both gastric bypass and diet groups (p<0.05*). Negative correlation between serum ghrelin and TC and LDL-c was preserved after intervention in diet group (p<0.05*).
Significant negative correlations between serum Ghrelin levels and serum Fasting blood sugar in the obese subjects before intervention in gastric bypass group and diet group (p<0.05*).
FBS in the sera of the gastric bypass, and diet groups showed higher levels as compared with the lean group.
In conclusion, the findings of the present study support the thesis that plasma ghrelin levels rise with diet-induced weight loss suggests that increased levels of circulating ghrelin may participate in the adaptive responses that constrain such weight loss. And Plasma ghrelin levels in subjects who underwent gastric bypass were markedly lower than those of both lean controls and matched obese controls, despite massive weight loss. Thus, whereas weight loss achieved by caloric restriction was associated with increased plasma ghrelin levels, that achieved by gastric bypass was associated with abnormally low levels. Low ghrelin values in the gastric-bypass group be explained by the fact that the subjects in that group had lost more weight than the matched obese controls, since weight loss should increase the plasma ghrelin level Thus, it seems clear that gastric bypass surgery is itself associated with decreased levels of circulating ghrelin.
These findings raise the possibility that markedly reduced ghrelin levels after gastric bypass suggests that suppression of ghrelin can now be studied as a potential mechanism by which this procedure causes weight loss. This hypothesis offers a plausible explanation for the paradoxical reduction of hunger between meals that occurs after gastric bypass.